Cut-off mechanism for tube machines



June 14, 1932.

J B. PLATT CUT-OFF MECHANISIV FOR TUBE MACHINES pril 22, 1931 Filed A ff A mllllllllilllllllllllllll Ess Patented June 14, 1932 UNITED STATES PATENT OFFICE f JAMES B. PLATTLOF BALTIMORE, MARYLAND, ASSIGNOR TO STONE STRAW CORPORA- TION, OIF WASHINGTON, DISTRICT F COLUMBIA, A CORPORATION 0F DELAWARE .into convenient lengths.

CUT-OFF MEC-IANISM FOR TUBE MACHINES Application filed April 22, 1931.

. This invention relates to cut-od mechanism for tube machines, and it comprises a freely rotatable knife or cutter mounted for orbital movement about an axis in a horizonal plane and, simultaneously, for revolution about a vertical axis, gearing for causing bodily movement of the knife about such horizontal and vertical axes, whereby the knife will be projected periodically into the path of a tube to be cut and, in approaching and receding from such path, will travel in the direction of movement of the tube, and guiding means for the tube for supporting it adjacent the point of cut; all as will be described hereinafter and as claimed.

In the manufacture of paper tubes of small bore, particularly those known as artificialv straws, it is common practice to form the tube on a mandrel and to feed it continuously from the mandrel to a mechanism for cutting it Inasmuch as the formed tube is continuously in motion as it is fed from kthe forming mechanism to the cut-offitis desirable to move the knife or V other cutter in the direction of movement lcause its rotation through drive gearing.

It has been found that the relatively slow rotation of a gear driven knife results in a speedy dulling of the blade to a point where imperfect cuts are made by it, this necessitating frequent shut-down of the machine for replacement of cutters with attendant loss of time and productivity. Moreover, the speed at which a gear driven knife may be actuated is decidedly limited. A speed suihciently high for efficient production is likely to set up destructive forces which might not Serial No. 532,091.

only cause damage to the machine but which would imperil the operator.

l have found that it is possible to operate cut-off mechanisms at higher speeds than have heretofore been considered practicable and at the same time to eliminate the defects and dangers attending the operation of prior art mechanisms at such high speeds. This has been accomplished by the present invention, wherein a freely rotatable knife or cutter is employed. An extremely high speed of rotation is imparted to it by a cutting operation in which it hits and passes through a paper tube into the path of which itis temporarily projected. rlhe knife, in rotating at such high speed not only e'ects a cleaner cut than a gear driven knife, but the blade does not readily lose its keenness and may be used for a considerably longer time than a gear driven knife before its replacement becomes necessary.

My invention therefore has as its object to increase the eiiiciency and productivity of tube making machinery by providing a knife which is rotated at high speed by hitting the tube to be cut, thereby to eil'ect a clean cut and to maintain the keenness of the cutting blade.

Other and further objects will be apparent from the following description and drawing, in which Figure 1 is a vertical sectional view of the cut-off mechanism comprising this invention,

Figure 2 is a top plan view of the mechanism, partly in section,

Figure 3 is a. fragmentary view, partly in vertical section at right angles to the section of Figure 1,

Figure t is a detail view, partly in section, of the knife mounting.

Referring more particularly to the draw ing:

A fixed housing 10, having a removable cover 11, is formed with a downwardly extending boss 12 which is iianged for the reception of screws or bolts to fasten it to the bed of a machine (not shown), and which Serves as a bearing for the vertical drive shaft 13. The upper end of shaft 13 is shoul- 3f dered for the support of a. rotatable turret 14 to which it is pinned at at 15, or is otherwise affixed. The turret comprises a base 16 and an upstanding annular Wall 17, spaced from the fixed housing.

The annular wall of the turret preferably has spaced circumferential flanges extending outwardly adjacent its upper edge, and its interior is formed with integral ribs 18 upon the upper ends Vof which are 'seated bearing' plates 19 and 20, held in position by screws 21 which are tapped into the ends of the ribs. As an additional support for the plates the interior wall of the turretmay be'machined to form an annular shoulder '22.

Another protuberance 23 is cast integrally with the wall 17 and is journalled to receive a vertical shaft 24 having a pinion 25 on its lower end (Figure 8) in mesh with an internally toothed gear 26 which is removably mounted in the fixed housing 10, as by screws 27. A bevel gear 28 is mounted on the upper end of shaft 24 and meshes with a bevel gear VQ9 on the cross shaft 30 which is received within a cut out portion of theplate 19 and 1s retained therein by a strap or bridge piece 31, the other end of the shaft being journalled in plate 20. Y

A crank 32, preferably ofdisk shape, is keyed to shaft 30 or ixedly mounted on it in any other well known manner, and the disk is radially slotted at 33 (Figure 4) for the reception of a stub shaft 34, one end of which is threaded for the reception of a nut 35 to hold it in position. A portion Vof the pintle 34 is of reduced diameter to define a shoulder against which a bearing cone 36 is seated. A second bearing cone 37 is shdably received on the pintle and is adjusted and retained thereon by a nut 38. An outer bearing race member 39 is revolvably and anti-frictionally supported on th-e pintle.l lt is shouldered at 40 and has a reduced threaded portion receiving a nut 41 which clamps the circular knife 50 against the shoulder. l

The turret 17 is slotted on opposite sides at 51Yand 52 for free passage of the knife beyond the confines thereofin its travel within the fixed housing, and the housing is hori- Zontally slotted at 53 so that'a circular tube guide 54 may extend through its wall into the pathof the knife 50. rlie guiderhas an annular groove 55 for tangentially receiving and supporting a tube to be cut, and is radially slotted at 56 for passage of the knife Y The guide supporting member l58 is preferably attached to the housing 10 by screws 63, the housing having cast therewith a base 64 (Figure 2) for such attachment.

A vertical arm 65 rises from the base 64 and receives a tubular guide 66 which has a. bell mouth 67 for Yreceiving a tube from the forming mechanism and directing it into the annular' groove in the circular guide 54.

ln operation, as the shaft 13 and turret 17 are rotated the pinion 25 which is carried by the turret, and which is in mesh with the fixed internally toothed gear 26, will be rotated, thus vdriving the shaft 24, the rotation of which is transmitted through the meshed bevel gears 29 and 28 to cross shaft 30, thereby rotating the disk 32 which is mounted on that shaft. The knife is thereby bodily revolved about shaft 30 and, simultaneously, is revolved about thevertical aXis of shaft 13. ln the compound orbital travel of the knife about both horizontal and vertical axes it will be projected periodically into the path of a tube which is supported by the rotary guide and will cut through such tube by pass ing through the radial slot in the guide.

The knife being freely mounted on its pintle will be rotatedby its impact against the tube in a cutting operation and a high speed of rotation will thus be imparted to it. rlhe knife, in rotating at high speed, not only cuts the tube cleanly and with facility, 'but does not readily lose its keenness and may be used for long periods without replacement.

l/Vhat l claim as my invention is 1. Cut-od mechanism for tubes comprising a guide, a circular knife freely rotatable upon a supporting pintle, andmechanism for projecting the knife periodically into the path of the tube with a slashing stroke which will impart rotation to the knife.

2. ln a cutting machine for tubes, the combination of a vfreely rotatable circularknife, means for revolvin the knife bodily about an axis offset therefrom,and a rotary support for said means having an axis of rotation parallel with the plane of rotation of said knife. f i Y' 8. The combination of two rotatable shafts, one driven by the other at an angle thereto, a freely rotatable cutter mounted for revolution about the aXis of the driven shaft the plane of rotation of said cutter being coincident with that of its revolution, and means for rotating both said shafts.

4. Cutoff mechanism for tube machines comprising in'combination, drive gearing, a freely rotatable knife actuated by said gearying and adapted to be projected outward at periodic intervals into the path of a tube to be cut thereby, a guide for said tube adapted to project it into the zone of cutting whereby contact of the knife against the tube in a cutting operation will impart a high speed of rotation to the knife.

CIP.

5. A cut-olf mechanism for tubes comprising a freely rotatable, circular knife mounted for orbital movement about a horizontal axis and, simultaneously, for revolution about a vertical axis, gearing for revolving the knife about such axes, and a guide for projecting a formed tube into the path of said knife, whereby contact of the knife therewith in a cutting operation will impart to the knife a high speed of rotation.

6. The combination with a stationary housing, a shaft having a turret secured thereto, the shaft and turret fitted to rotate within parts of the housing, a stationary gear surrounding the shaft and secured to the housing, of two shafts journalled in the turret at right angles to each other, each having a transmission gear whereby the motion of one is imparted to the other, and one having a gear engaging the teeth of the stationary gear, whereby it is rotated by reason of the rotation of the turret within the housing, a crank secured to one of the shafts, a freely rotatable circular cutter carried by said crank, said crank adapted to project the cutter periodically into the path of a tube to be out upon rotation of said shafts, whereby in a cutting operation rotation will be imparted to the cutter by its passage thorugh the tube to be cut.

'l'. In a cutting machine for tubes, the cornbination of a freely rotatable circular knife, means for revolving the knife bodily about an axis offset therefrom, and a rota-ry support for said means.

In testimony whereof I aiiix my signature.

JAMES B. PLATT. 

